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Discussion Starter #1
HI,

Does anyone know the procedure for testing the ABS sensors? I'm getting the DSC, parking break, ABS lights on at times. This happened 2 or 3 times while the car was under warranty and in every ocassion the problem was fixed by either cleaning or replacing one of the wheel motion sensors, so I bet it's the same thing again.

Thanks

Pancho
 

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Discussion Starter #2
Bump...

Anyone?

I still get the intermitent failure, although much less than before. Perhaps because I cleaned the rear sensors when doing the RTABs.

I remember once the tech said that he had measured one of the sensors and it was marginal so he replaced it. I bet he did this with the car's computer itself, which would take me to asking about software than can read DSC failures, I don't think there is one, is there?

I'd hate to have to take my car to the stealer because of this..

Pancho
 

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The OBDII code readers will not read the ABS signals. I had the same problem as you had. An indy repair center I use charges me $10.00 to read the code with a very expensive analyzer. The wheel speed sensor repair was $100.00 for the part and $95.00 for the labor.
 

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To the OP. Jack and remove the wheels. Disconnect the wheel speed sensor(s) from the harness in the wheel well. You***8217;ll need a digital volt meter (DVM). Connect the meter leads to the wheel speed sensor - polarity doesn***8217;t matter. Select the milivolt range (mV). Spin the hub and observe the meter. You should read between 1 and 5 mV when you spin the hub. No output = a defective and/or dirty sensor. Cheap and effective. Good luck.
 

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The OBDII code readers will not read the ABS signals. I had the same problem as you had. An indy repair center I use charges me $10.00 to read the code with a very expensive analyzer. The wheel speed sensor repair was $100.00 for the part and $95.00 for the labor.
Ouch on the labor.. these things are 1 hex screw and 2 minutes to replace, you can even do it w/o removing the wheel.
 

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To the OP. Jack and remove the wheels. Disconnect the wheel speed sensor(s) from the harness in the wheel well. You'll need a digital volt meter (DVM). Connect the meter leads to the wheel speed sensor - polarity doesn't matter. Select the milivolt range (mV). Spin the hub and observe the meter. You should read between 1 and 5 mV when you spin the hub. No output = a defective and/or dirty sensor. Cheap and effective. Good luck.


Wow, great info - I'm going to add this to the wiki.
 

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Discussion Starter #9
To the OP. Jack and remove the wheels. Disconnect the wheel speed sensor(s) from the harness in the wheel well. You'll need a digital volt meter (DVM). Connect the meter leads to the wheel speed sensor - polarity doesn't matter. Select the milivolt range (mV). Spin the hub and observe the meter. You should read between 1 and 5 mV when you spin the hub. No output = a defective and/or dirty sensor. Cheap and effective. Good luck.
Great info. I will try this. Not sure I can spin the rears but we'll see.

Thanks

Pancho
 

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Sorry, Dumb Question. Is there a picture of it and location of the plug anywhere? I used the Peak and couldn't read any errors but the ABS and DSC light is on and stay on. Another issue that I have had lately is that the tail light brake warning lights have came on 3 times and went out by themselves.. All lights were fine. I love my Bimmer but Why are they so finiky?

Thanks in advance.
 

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I'm trying to do this wheel speed sensor test right now on a 2003 M3. We tested both fronts and got a 0 reading from each. If it's a valid reading, which I'm seriously doubting, wouldn't we have some idiot lights illuminated on the dash if both sensors were failing?

I fashioned a harness from some spare contacts I had that fit the pins well, so I'm sure we're getting a good connection to the sensor. I've also measured a steady voltage from my battery using the DVM, so it appears to be functioning correctly also.

Any help appreciated!


Sorry, Dumb Question. Is there a picture of it and location of the plug anywhere?
The front plugs are in a black plastic box inside the fender well on the engine side. Open the box and look for the blue connector, at least it's blue on the 2003 M3 I'm looking at right now. Remove it from the box, disconnect it by pressing the button and pulling it apart.
 

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Sorry, Dumb Question. Is there a picture of it and location of the plug anywhere? I used the Peak and couldn't read any errors but the ABS and DSC light is on and stay on. Another issue that I have had lately is that the tail light brake warning lights have came on 3 times and went out by themselves.. All lights were fine. I love my Bimmer but Why are they so finiky?

Thanks in advance.
As noted above, the cheaper code readers Peake, etc. can't read the more complex codes from the ABS systems so you won't be able to get any feedback. You can either try the volt meter DIY up above or take it to a dealer or Indy who has one of the more expensive readers to get a read on which wheel sensor is bad.
 

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JVR826.
fyi there's a current limiting fuse inside your volt meter, i've had it blow before by measuring voltage with the leads plugged into the wrong holes.(the ones for mA measurment). overloaded the fuse and pfft. you can still read voltage even with a bad fuse due to a different circuit path through the meter. but current readings alwasy indicated incorrectly until i replaced this fuse. might check and make sure your fuse is good before ruling the sensors as failed. peace!
 

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Thanks Cherokee. My DVM is a fairly inexpensive one. I need to upgrade it for sure.

We ended up removing and cleaning the two front sensors we checked since we were there anyway. They appeared quite dirty and had some minor metal shavings stuck to the magnets. A very spirited drive later, the problem seems twarted at this point. We do need to get at the rear ones and clean them too I think.

The issue surfaced last weekend at California Speedway HPDE. The driver experienced DSC kicking in at turn 9 (at the right/left/right/left/left combo) before entering the front straight on the oval. He'd brake hard after that infield straight, get DSC as he applied power to go thru the combination, and it would stay on thru that whole section. I wasn't in car with him, but his instructor confirmed it wasn't normal. Thing is, the car was fine on Saturday, but Sunday afternoon it started acting up.

I'm hoping the cleaning resolves the issue. We'll be at Thunderhill on Friday and I'll be able to ride along and see how it performs.
 

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The front plugs are in a black plastic box inside the fender well on the engine side. Open the box and look for the blue connector, at least it's blue on the 2003 M3 I'm looking at right now. Remove it from the box, disconnect it by pressing the button and pulling it apart.

Anyone have a good description of where the rear sensors are? I shredded a tire last week and am experiencing all of the previously listed symptoms. I'm pretty confident that replacing the sensor will do the trick. Thanks in advance,
-A
 

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Ouch on the labor.. these things are 1 hex screw and 2 minutes to replace, you can even do it w/o removing the wheel.
what are talking about, some of us spent 30 min to 1hr trying to take them out, sometimes they get stuck and you'll have to drill them out, other times it takes 2 min.

thanks
 

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To the OP. Jack and remove the wheels. Disconnect the wheel speed sensor(s) from the harness in the wheel well. You'll need a digital volt meter (DVM). Connect the meter leads to the wheel speed sensor - polarity doesn't matter. Select the milivolt range (mV). Spin the hub and observe the meter. You should read between 1 and 5 mV when you spin the hub. No output = a defective and/or dirty sensor. Cheap and effective. Good luck.
Good info. Thanks.

Search and you will find :D
 
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